Snap acting pneumatic pressure pilot



May 13, 1952 Filed Feb. 19, 1946 G. F. BROCKETT SNAP ACTING PNEUMATICPRESSURE PILOT 3 Sheets-Sheet l May 13, 1952 G. F. BROCKETT 2,596,366

SNAP ACTING PNEUMATIC PRESSURE PILOT Filed Feb. 19, 1946 3 Sheets-Sheet2 III.

17221 21201: 676/17: FBioCkeZt.

y 1952 G. F. BROCKETT SNAP ACTING PNEUMATIC PRESSURE PILOT Filed Feb.19, 1946 5 Sheets-Sheet 5 Patented May 13, 1952 SNAP ACTING PNEUMATICPRESSURE PILOT Glenn F. Brockett, Marshalltown, Iowa, assignor to FisherGovernor Company, Marshalltown, Iowa, a corporation of Iowa ApplicationFebruary 19, 1946, Serial No. 648,668 3 Claims. (01. 137-153) Thisinvention relates to pneumatic pressure pilots, and particularly thequick acting, or snap acting type.

Three principal elements of the pilot of my invention consist of aflapper for closing a bleed port of an air pressure system, magneticmeans for moving the flapper to port closing position, and an operatingmeans for moving the flapper to port opening position.

I have provided that in the operation of the flapper energy is stored upto such a point that once the flapper is moved it is done quickly. Thismay be done either by making the flapper itself flexible, or providingsimilar action in the means for operating the flapper. The flapper isheld in port closing position by a magnet, and when the force tending tomove the flapper to port opening position comes into play, it builds upenergy gradually which overcomes the attraction of the magnet and doesso decisively and virtually instantaneously.

The invention is adaptable where air pressure is utilized as anoperating medium, or where it is used as a control medium.

An object of the invention is to provide that where air pressure is usedto cause flow from an oil well, the pilot automatically permits flowwhen the air pressure is sufiiciently high and cuts it olT when the airpressure drops below the desired minimum. In this instance the pilot isoperated from the same source of air pressure as that used for the well.

Another object of the invention is to provide automatic liquid levelcontrol. The pilot is operated by a source of air pressure, and controlsvalve means for the liquid. The action of the air pressure on the pilotis responsive to the level of the liquid being controlled.

Still another object is the provision Of a quick acting, and thereforequickly responsive pilot.

A further object is the provision for reversing various of the parts ofthe device and accordingly reversing its action.

A still further object is the provision of simple means for adjustingthe range of operation of the pilot. This range can be adjusted as toits limits and its position.

With these and other objects in view, my invention consists in theconstruction, arrangement and combination of the various parts of mydevice, whereby the objects contemplated are attained, as hereinaftermore fully set forth, pointed out in the claims, and illustrated in theaccompanying drawings, in which:

Fig. 1 is a view partly in section and partly in diagram of one form ofcontrol device;

Fig. 2 is a view similar to Fig. 1, with some of the parts reversed forreversing the action of the device.

Fig. 3 is a view partly in plan and partly in diagram of another form ofcontrol device;

Fig. 4 is a sectional view taken on line 4-4 of Fig. 3;

Fig. 5 is a sectional view taken on line 5--5 of Fig. 3;

Fig. 6 is an enlarged side view of the liquid level setting device ofFig. 3.

Fig. '7 is a fragmentary view of a tank in horizontal cross section withthe liquid level setting device connected to a float mechanism; and

Fig. 8 is a view similar to Fig. 3 with some 01' the parts reversed forreversing the action of the device.

Referring now in detail to the drawings, it will be observed thatvarious items are exaggerated in size for the purpose of showing themmore clearly. Figs. 1' and 2 show a control pilot for controlling airpressure for operating a diaphragm motor valve. Its essential partsconsist of a supporting panel I2 upon which is mounted a supportingbracket l4 pivoted on the panel by a pivot bolt l6 threaded into thepanel l2. The supporting bracket I4 is maintained in position andadjusted about its pivot by an adjusting arm 18 pivotally secured to thebracket l4 at a point spaced from the pivot point [6 as indicatedat 26,and the other end of the adjusting arm is supported on the panel 12 by abracket 22. The adjusting arm [8 is reciprocated to the right or left bymeans of a control point adjustment screw 24 and. a compression spring26 acting on th arm I8 through the bracket 22.

A bleed nozzle construction in the form of a block 23 ismounted on thebracket l4 and contains two chambers 30 and 32 with a fixed oriflce 34interconnecting the two chambers, and a nozzle or bleed port 36 openingfrom the chamber 32 to atmosphere. A projection 38 extends from theblock 28 for supporting a permanent magnet 49, the magnet 40 beingadjustable by bolt 42 threaded in the projection 38.

The bleed port 36 is adapted to be closed by one end of a flat springsteel flapper 44 which is pivotally secured at its other end to aBourdon tube 46. A fixed pivot post 48 is secured to the supportingbracket l4 adjacent to the flapper 44 and intermediate its ends. TheBourdon tube 46 is fixedly secured at one point to the panel I! mallyclosed by spring I when'air pressure'is' released from chamber 12therein under diaphragm 14. Pressure on being built up in the chamber'12 opens the valve.

The oil well is operated by an independent source of compressed air inan .air line 16 which.

is connected with the well casing 18. When sufficient air pressure isbuilt up in the well casing it forces oil out the oil line 66. Anotherair line sc eads' oil? the line 16 and is connected to the Bourdon tube*46'which: is hollow and uncoils when air pressure is built up within itand recoils-when the pressure drops.

Figel shows the flapper 44 against the nozzle orbleed-port 36 andclosing the same. Compressed air from the line 56 enters chamber 30 andfr om there' the "chamber: 32, and since the bleed port 36 is closed,air pressure builds up through theline62 to the chamber 12 in thediaphragm motor valveii i; This thenoperates the valve 64-and unseatsit. When there is suffleient compressed air in the lin 16 and in thewell casing." to 'force the 'oil out of the well, the air pressure inthe line 80 builds up in the Bourdon tube which expands: The Bourdontube in expanding actually uncoils, thatis, its point'of 'connectionwith the flapper. 44 moves to the-rights WhenJthe' pressure dropsxandthe Bourdontube'recoils; its point of connection with the.flapper44imoves totheileft; When the Bourdon: tube re'coilstiit operates: theflapper 44' about a -fixe'd' ipivot 48j and'.moves.the opposite end ofthe flapper' 4450i? oi the 'bleedport 36..and permitsfithes airfroniichamber 32 ;;to .bleedto atmos: here... Then: the pressureainthediaphra'gm motor-valve :dropsand the-valve closes.

"Iheflapper '44 is attracte'd' to. closed position against the bleedport -36-by the permanent magnetai4ll." This magnet is-adjustable bymeans of threaded .bolt42 toward and away'iromthe flapper; 44;!Adjustable-stop "5Z-is for limiting the movement iof theflapper 44 inthe opening direction;-

Thepilot' is operable-within certain set maximum and minimum.limits-ofair pressure inthe 'wellcasing 'l8. To vary: the rang 'betweenthe the maximum and the minimumlimits, the per-'- manent magnet 40is-moved' toward and away from theflapper- 44. When the magnet 40 ismovedz'towa'rd the flapper 44 the range of operation' is widened, andwhen it ismoved away fromtheflapper, 44therange is narrowed. Forpositioning .therangewithout .varying the-extent of the range, the arm18 is moved to the right or left by the screwhead 24. When it is movedto-the left it lowers the range-that is, it sets the pilot to operateat'lower pressures, both minimumand maximum; By moving the arm l8 to theleft the. fixedpivot lflbeingalso moved to the 1 left; the air pressurein the' Bourdon tube 46 must be lowered still more in order. to recoilsufiicientlyto move? the flapper. off of the bleed port- 36. Also themaximum limit of air pressure need not be so great, that is Bourdon tube46 njeed' not uncoil tosuch. agreat extent in order to take the tensionoff the flapper 44 to permit it to be attracted to port closing positionby the magnet 40.

The flapper 44 is flexible steel and because of this characteristicsnapping action takes place. When the Bourdon tube 46 recoils, tensionis built'up in the flexible flapper 44. The Bourdon tube does'not movethe flapper off the bleed port 36 gradually because the attraction ofthe magnet 44 is greater than the initial tension in the flapper;butwhen -tension in the flapper 44 becomes great enough that it isunseated off of the bleed port 35,=it 'unseats by snappingaction becauseof the sudden loss of the attraction force of permanent'magnet 4D. Theforce of a ma neton. an object varies inversely with the square of thedistance from it, and once the flapper is moved a distance away from themagnet it is out of its efiective range.

The pilot is operable andusefulin'connectiOn withioil wells whether theyare operatedbysar tiflcial supply of air pressure, or by -a naturalsupply of pressureirom within the well itself.

When the pressure-is-built up sufficiently the valve 64 opens and oilflows. In the case ofwells operated by a'natural supply of air pressure,the pressure is not always constant, .but builds upat intervals and theintervals are not always uni form. The pilot eliminates :thetimingelement and causes thewellto flow only when sufficient pressurehas built'up in the well casing.

In adapting the pilot to a well which v is operated bynatural gaspressure in the well, the

gas from" the well is used in theline-Elflfor-operating the Bourdontube, as shown in the'draw- V ings, and it is alsousedin the line-56 asan operating medium for opening the valve .64. It will be understood;therefore, that anyreferenceto air pressure. will include both anartificial .sup

ply of compressed air and natural gas. pressure from. thewelL-and thisistrue whether .such reference is in the specification or, claims.

The pilot is adapted to bereversed. Thear rangement shown in Fig.lprovides thatthe pressure is bled from thediaphragm valve 64 ondecreaseof control pressure in the line 88; and the yalve-65 of Fig;2.is bled on increase of icontrol pressure in theline 84. In Fig. 2thenozzle block 23 and the magnet 40' are reversed to the oppositesideof the flapper 44, as are also the adjustable stop 52 and the fixedpivot 48. When air pressure is built up, in .the Bourdon tube 46 fromtheair line it uncoils and unseats'the' flapper 44 off thebleed port 36;and

when theair in' the -chamber;32 then bleeds to atmosphere it releasesthe pressure in the motor diaphragm valve 65 and permits it to be openedby the spring 10. When the air pressure drops in the Bourdon tube 46 itrecoils, moving to the left, and permits the flapper. to be attracted tothe port closingposition by the magnet 40, builds up pressure in thevalve 64 and closes it. I

The air lines 56'and S2=attheirpoints of connection with the nozzleblock-28 are flexible, so as to accommodate-placingthe nozzle block inits alternate positions, as well as to allow for its angular movementwhen thesupporting. bracket I4 is adjusted; The valve 65 is the reverseof valve 64, the'former being normally held open by the spring Handclosed by the air pressure on the diaphragm l5.

It is intended that the arrangement of either Fig. 1 or Fig. 2 can beused withother than. oil

pressure-can be supplied to the line 80 and Bourdon tube 48, and thevalve 84 or 85 can be used in any line in which there is a flow offluid.

An embodiment of the snap acting pilot as applied to liquid levelcontrols is shown in Fig. 3. In this embodiment a supply of compressedair is connected to the line 82 which is provided with a standard gaspressure regulator 84 for assuring a constant pressure. This line 82leads to nozzle block 88 and the chamber 88 (see Fig. 5) therein fromwhich a fixed orifice 90 leads to another chamber 92. From the chamber92 a bleed port 94 leads to atmosphere. From the chamber 92 a line 98leads to diaphragm motor valve 98 to the chamber I therein under thediaphragm I02. The valve 98 is held normally closed by a spring I04 andis opened when air pressure is built up in the chamber I00.

The pilot equipment is mounted on a supporting panel I08 upon which aremounted two supporting brackets I 08 and I I 0. In the arrangement ofFig. 3 the nozzle block is'mounted on the bracket I08. A permanentmagnet H2 is positioned near the bleed port 94 and is mounted in placeby an arrangement shown in Fig. 4. The magnet H2 is secured by bolt II4extending through the magnet and through a flexible strip II8 into boltII8 which has an enlarged block at its outer end. Bolt I I8 is threadedinto the shank of the screw I20 which in turn is threaded into a barI22. The bar I22 is secured to the nozzle block 88 by means of bolt I24.By this arrangement the magnet II 2 is adjustable in a line parallelwith the nozzle block 28 by turning the thumb screw I20.

A level adjustment mechanism is indicated generally at I and contains ametal flapper I28 adapted to close the bleed port 94 and is attracted toport closing position by the magnet II2. Reference may be had to Figs. 6and 7 for a showing of the proper mounting of the level control I28. Thenumeral I30 indicates a water supply tank which is fed by the line I32supplied from a convenient water source and in which valve 98 isinterposed. The tank I30 is provided with a float I34. Fig. 8 is ahorizontal cross section looking down at the float I34 and on change oi.level of the water in the tank it moves toward and away from theobserver. An arm I 38 is connected to the float I 34 and is connectedwith a rotary shaft I38. The level control device is secured to theouter end of the rotary shaft I38 by means of flange I40 which is boltedto flange I42 mounted on the level control mechanism I28. A shaft I44 isloosely mounted in the body I48 of the level control I 28 and throughthe front face I48. The flapper I28 is loosely mounted on the shaft I44.A clip I50 having two lateral ears I52 is pivotally mounted at I54 onthe body I 48, one ear I52 being on each side thereof. A threaded boltI58 having an eyelet I58 at one end thereof is inserted in an opening inthe clip I50 and is provided with a pin I80 through the eyelet andextends through the front face I 48. A knurled knob I82 is threaded ontothe other end of the bolt I58. A compression spring I84 biases the clipI50 outwardly from the front face I 48. The side ears I52 are providedwith camming surfaces I88 which are raised and lowered as the clip I50is rotated about its pivot point I54. As the knurled knob I82 is turnedon the threaded bolt I58 one way or the other the clip I50 is broughttoward or let out from the front face I 48, thereby raising or loweringthe camming surfaces I88. The metal flapper I 28 extends outwardly fromthe level control device I28 to the left. as shown in Fig. 3 and thisflapper also may be flipped over to extend out to the right, resting onone of the camming surfaces: I88 depending on which direction itextends. On the outer surface of the front face I48 is a dial I88 tomark settings for the knob I82. In the arrangement of Fig. 3 the flapperI28 extends to the left 'to cover and close the escape port 34 and isattracted to port closing position by the magnet II2. An adjustable stopH0 is secured to the supporting bracket I08 opposite the bleed port 94to limit the extent to which the flapper I28 can be moved off the escapeport 94.

At any given setting of the knob I82, as the water level in the tank I30rises, the float I34 rises rocking the arm I38 and also the rotary shaftI38. When the water level reaches a predetermined height the levelcontrol I 28 is rotated clockwise as shown in Fig. 3, raising theflapper I28 off of the bleed port 94 and permitting the escape of airpressure from the interior of the nozzle block 88. Air pressure therebyalso escapes from under the diaphragm I02 in the valve 98 permitting thevalve to be closed under the action of the spring I04, and cutting offthe flow of the water to the tank I30. When the water lowers to apredetermined level the rotary shaft I38 and the level control deviceI38 is rotated counterclockwise as viewed in Fig. 3. When this motionhas continued a suflicient extent the pressure of the camming surfaceI88 is released from the flapper I28 and the magnet I I 2 attracts theflapper I28 to port closing position as shown in Fig. 3. This thenbuilds up the air pressure through the nozzle block 88 to the valve 98and opens the valve, permitting water to flow to the tank I30.

As with the pilot in Figs. 1 and 2, this: pilot is also snap acting.While the flapper I28 itself is not flexible, torsion in the rotaryshaft I38 is utilized for producing snap action. Energy is built up inthe rotary shaft I38 by rotating against the force of the magnet II2which tends to hold the flapper I28 in port closing position. Energy isbuilt up in the shaft I38 to overcome the attraction of the magnet H2,and once that attraction is overcome the flapper moves away from themagnet by a snap action as described in connection with Fig. 1.

Also as in the instance of Figs. 1 and 2, this pilot is adjustable forvarying the maximum and minimum levels in the tank I30. When the magnetI I2 is moved toward the flapper I28 the range between the upper and thelower levels is increased, and. when the magnet I I 2 is moved away fromthe flapper I28, the range between the maximum and the minimum level isdecreased.

To position the range without varying the extent of the range itself,the level control device I28 is adjusted. By turning the knob I82counterclockwise as viewed in Fig. 3 both the maximum and the minimumlevels are raised. By so turning the knob I82 the clip I50 is permittedto swing away from the front face I48 lowering the camming surface I88and also lowering the flapper I28. In order for the float mechanism tolift the flapper off the bleed port 94 it must then rise to anadditional height to unseat the flapper I28. The reverse is also true;when the camming surface I88 is raised to a higher position, the levelof the water need not rise to such a great height to unseat the flapper.

Air pressure meters can be attached to lines 83 and 91 to indicate thepressures in the respective lines 82 and 98.

7: "seal prrerersiblet sis en let bpwn ir lin c196 exte d across the supqrt s: panel; H1 n an e apped te ther qthe brackets 10, r 9- h oz legbqckxfi a dth m s et ss mb i 1 can bo ng nted onthebracket H as shown inFig. 8,. and the-lines Qfiand B2 tapped for connecting up to, the nozzleblock 86. Inthis instance the flapperflzs is fiipped over to the rightto close -the escape port 94, and is held in closed position bythe.;magnet. I i2: in; its;new.position. In this ar rangement, when thewaterlevel in the tankltil has reached its upper; limit the flapper 129is in port closing position-as shown in Fig, 8, thereby order. to raisethe respective levels at which the pilot will operate, the. knob IE2 isturned in a clockwise direction. This tightens the knob !62 drawing theclip I59, toward the front face I48 and raising the camming surface 169.When the, camming surface is-raised to a higher posi tion, the waterlevel must rise to a greater height to. rotate the level control device125 sufficiently for the flapper 128. to close the escape port 94. In alike manner, when the camming surface I95 is adjusted to a lowerposition the flapper I22 restsflower, and the water level need not riseso highto permit theflapper to come to port closing position, The dial168 is reversible for indicating which direction to turn knob, 192 forraising the liquid levelinthediiierent positions of the device.

While I have herein shown and described a preferred embodiment of myinvention, manife tly it is. susceptible of modifications. andrearrangement of parts without departing from the spiritand scopethereof. I do not, therefore, wish to be understood as limiting thisinvention totheprecise form herein disclosed, except as I term, a} leverpivoted on said second support at a pcintspaced from the .pointwheresaid second supportisswingablyconnected to first support and having anend portion swingable in op posed relationship to said port to open andclose said port, a Bourdon tube having one end mounted on said firstsupport and responsive to said varying fluid pressure, the other end ofsaid 'Bourdon tube being connected to said lever adjacent the leverpivotpoint, and adjustable stop means carried by said second support forlimiting levermovernent away from said port.

2. A device for use with a conduit system to cqntrel lcwthsethrousliinprede minedir l ehipftw r in -flu d res compris g: rst po t;a. e t, w s blwoenect d fiaid first p il d us l l n th n on 22 v t lconnected to said second support and havingits other-end'mounted on saidiirst support and operative on adjustment of the link length to 'varytheangular relationship; between said we supports, a, conduit havinga portcarried by 'said secondsupport and adapted tobe connectedto said conduitsystem for dischargethroughsaid port of 'fluid flowingirorn said conduitsystem,

me ns. or. losi i r clu n atte .v rri d b a d rs up er-tens; w lsa fib ad r m' d rt a top me be ef iedhy said second support for limitingportope 'ng m n of s i ap r nd pr reseneti m jsca e by 'fi st u ort e'sjonsireto a d v r n flui r s u firativfleiactu-I ate said flapper.

3. A device for' use with a conduitsystem to control flow therethroughin predetermined rela tionship to a varying fiuid pressure, said devicecomprising a first support, a second support swingably connected to saidfirst support, a li'nk; of adjustable length having one end pivotallyconnected to said second suDPQ t and having its other end mounted onsaid first support and operative on adjustment of the link length tovary the angular relationship betweensaidtwo supports, a conduit havinga port carried by said second support and adapted to be connected tosaid conduit system for discharge through said port of fluid flowingfrom said conduit system, means for closing said port including aflapper for said second support, astop member car ied by said. secondsupport for limiting port opening movement of said lever, and pressuresensitive means carried by said first support responsive-to said varyingfluid pressure and operativeto actuate said fiapper-for port closingmovement, said link extending in general-parallelism with the directionof motion of said flapper, said flapper extending generally transverselyto said link, and the pivotal connection between said two supports beingdisposed generally in the plane of said flapper extending transverselyof said second support.

GLENN F; BROCKETT.

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468,440 Fortier Feb. 9, 1892 982,229 Adair Jan. 24, 1911 1,412,773Colgate Apr. 11, 1922 1,605,355 Fisher Nov. 9, 1926 1,641,944 BristolSept. 6, 1927 1,875,511 Shivers Sept, 6, 1932 2,185,671 Kimbull Jan 2-,1,949

2,263,771 Grifiey Nov; 25 194-1 2,264,262 Erbgutti Nov. 25, 19412,298,112 Edwards Oct. 6, 1942 2,332,627 Erguth Oct. 26, 1943' 2,356,970Brockett Aug. 29, 1944 2,427,235 Smoot Sept. 9,. 1947 FOREIGN PATENTSNumber Country Date 74,521 Austria of 191.8 589,617 Germany of 1933

